In the past, the coupling and uncoupling of railway cars usually required a trainman to stand between the cars to effect the locking and releasing operations. In recent years, conventional railway cars have been supplied with automatic coupling devices which enable the connection and disconnection to be completed without direct manual operation. Now, the Railway Safety Rules of the Department of Transportation have been extended to require that track motor cars, which are used to carry track maintenance crew and equipment, be provided with couplers which can be coupled and uncoupled without requiring one to go between the ends of the cars.